1. Field of the Invention
The present invention relates to a window-glass heating device for heating a window glass for a vehicle such as automobile in order to secure the visibility thereof, specifically, in such a manner as to attach a conductive thin film to the window glass and to electrify it.
2. Description of the Related Art
A window glass for an automobile or the like is provided with a heating device to prevent fog, frost, freezing, ice and snow attached on the window glass from occurring in order to secure a visibility of a driver.
For example, Patent Document 1 describes that a glass heating means provided with a glass heater and an air conditioner blowing hot air to the window glass are controlled in accordance with visibility state of the vehicle window in order to eliminate icing and condensation conditions of the window.
Also, Patent Document 2 describes that a glass heating wire is formed in the rear window glass of a vehicle as a defogger, and that an electric power supply channel from a power source to the glass heating wire is switched by a simple circuit to reduce a battery load. Besides, Patent Document 3 describes that a resistance-heating wire is disposed in-between a laminated glass in a windshield wiper reset area in order to prevent the windshield wiper from freezing on and adhering with the front window.
Further, Patent Document 4 describes that a window glass for building is provided with an exothermic paint, a heating carbon plate, a resistance-heating metallic element, a silicone sheet like heating element and the like on its surface to heat the window glass.
Patent Document 1: Japanese Patent application Laid-Open No. H05-147500
Patent Document 2: Japanese Patent application Laid-Open No. H11-170986
Patent Document 3: Japanese Patent application Laid-Open No. H10-189232
Patent Document 4: Japanese Patent application Laid-Open No. H10-139492